This invention relates generally to flashlights and, in particular, to a pocket flashlight of the push button type.
Pocket flashlights such as disclosed in U.S. Pat. No. 4,484,253 to I. J. Roberts have utilized conventional push button mechanisms previously used in ball point pens. In the Roberts flashlight, a push button mechanism and a bulb are located at opposite ends of a cylindrical casing which contains a pair of batteries. The push button mechanism is operated to move a long slender wire (about the same diameter as paper clip wire) inside the casing so that the wire slides into and out of electrical contact with a collar disposed around the bulb. The electrical contact between the wire and the bulb collar forms a "switch" for illuminating the bulb.
A drawback of the Roberts flashlight is that this "switch" is located at one end of the casing but is operated by the push button mechanism located at the other end of the casing. Furthermore, the electrical contact between the wire and the bulb collar is not a positive connection and is influenced by the length of the bulb, the assembly of the bulb and the collar, the shape and location of the bend in the end of the wire adjacent the bulb collar, and the lack of positive pressure urging the wire into electrical contact with the bulb collar.
The Roberts flashlight has another drawback in that replacement of the bulb and the batteries is often a difficult and tedious procedure. This is because the long slender wire must be carefully removed from and then reinserted in the casing without pinching, twisting, kinking, bending or otherwise distorting its shape. A further drawback of the Roberts flashlight is that the casing must have an inside diameter large enough to accommodate the batteries and the wire, thereby resulting in the casing having a larger than desireable outside diameter.